Gasketed mechanical couplings are used to connect pipe segments in an end-to-end relationship. Known preassembled mechanical couplings, such as for example those shown in U.S. Pat. No. 4,522,434 include one or more housing segments that are joined by two or more mechanical fasteners, e.g., bolt and nut assemblies; to form opposed end face openings of the coupling into which the pipe segments may be inserted. Each housing segment includes a pair of arcuate surfaces which define a portion of the end face opening for engagement with an outer surface of the pipe segment, such as for example the circumferential groove in standard grooved-end pipe, to prevent axial separation of the pipe segments. In some known couplings, the arcuate surfaces are defined by a radius of curvature that is greater than the radius of curvature defined by the outer surface of the pipe in order that the pipe segment may be inserted or “stabbed” into the coupling preassembly. Once the pipe segment is inserted into the preassembled coupling, the fasteners are tightened such that the housing segments are deformed to conform to the outer surface of the pipe segment to form a close engagement between the arcuate surfaces and the pipe. Accordingly, the radius of curvature of the arcuate surfaces of the housing segment is altered. Alternatively in other known couplings, for example, those shown in U.S. Pat. No. 4,471,979, the housing segments of the coupling are not deformed. Instead, the pipe or tubing to be joined is deformed to conform to and engage the arcuate surfaces of the coupling housing segments.
For coupling preassemblies in which the housing segment is deformed, installation of these known preassembled couplings can be difficult or complex due to the torque requirements in tightening the coupling fasteners to deform the housing segments about the joined pipe segments. The installation can be further complicated depending upon the orientation, location and/or accessibility of the preassembled coupling and its fasteners, which may affect the accessibility of the fasteners.